"I'm not quite as confident with that as I was maybe a week ago," Servais said. "It's going to take him a little time. You're not just going to fire him out there and expect six innings and 100 pitches right out of the chute. That's not fair to him.
"So once we get closer to getting him playing catch and moving around better, then we can start putting plans together that way. The longer it goes from when he's pitched, the longer it takes to build him back up again."
Hernandez is on the disabled list for just the third time in his 12-year career and the first time since 2008. He felt pain in his calf while doing pregame stretching on May 31 and was placed on the DL retroactive to May 29, the day after his last start.
The six-time All-Star is 4-4 with a 2.86 ERA in 10 starts, but his string of eight straight seasons of 200-plus innings clearly will be snapped now as he's already missed three outings and it's becoming clear now he won't return until sometime in July.
For now, Hernandez is limited to playing catch while sitting in a stool in order to keep his arm active, while not putting any weight on his pushoff leg.
• Hard-throwing rookie right-hander Edwin Diaz will likely be unavailable for the rest of the Rays series after throwing 32 pitches over 2 2/3 innings of scoreless relief in Tuesday's 8-7 loss.
"We'll give him a day or two to see how he's feeling," Servais said. "He is very resilient. Every day he was doing this in the Minor Leagues, he always came back. But  stressful pitches in the big leagues is much different than the Minor Leagues."
• The Red Sox are recalling former Mariners lefty Roenis Elias from Triple-A to face Seattle's Hisashi Iwakuma on Friday in the opener of a three-game series at Fenway Park. Elias, who was part of the trade that brought Wade Miley to Seattle, is 4-3 with a 3.54 ERA in 10 games for Pawtucket. He pitched once in relief for Boston earlier this season, allowing three runs in 1 2/3 innings against the Astros on April 23.
Miley will start Saturday in that series for the Mariners against Rick Porcello, with Taijuan Walker slated for Sunday's start against Red Sox ace David Price.
Greg Johns has covered the Mariners since 1997, and for MLB.com since 2011. Follow him on Twitter @GregJohnsMLB and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.